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Simply Sustainable. Always Effective.
Control of Bacterial Leaf
Blight in Onions
Control of Bacterial Leaf Blight with
OxiDate 2.0 in Onions, 2011
Researchers: Dr. Howard Schwartz, Kris Otto, & Mark McMillan
ARDEC, Colorado State University
Crop: Seeded Yellow Onion (Allium cepa ‘Granero’)
Features & Benefits
•Zero-Hour REI,
Zero-Days to Harvest
•Exempt from Pesticide Residue
•No Mutational Resistance
•Also Effective Against Bacterial
Soft Rot & Botrytis Storage Rot
Organism: Bacterial Leaf Blight (Xanthomonas campestris)
Bacterial Leaf Blight (BLB) in Onion caused by bacterium
Xanthomonas campestris can cause significant blighting of
outer leaves resulting in stunted plants and reduced size of
bulbs. The disease favors high temperatures, coupled with
humid and overcast conditions. Copper based fungicides
control BLB with only mixed results and there is concern
about pathogen resistance.
The objective of this study was to evaluate OxiDate 2.0 as
a copper alternative to control BLB in Onions. Transplanted
yellow onions ‘Granero’ were planted on April 18, 2011. Plants
were evaluated for percentage of leaf blight, phytotoxicity, and
total yield.
Application Program
• Treatments were applied starting
two weeks pre-bulbing with a total of
six sprays applied every seven days
(07/11/11-08/15/11).
• Plants were inoculated with
Xanthomonas at seven and 14 days
post-bulbing (07/22 and 07/29).
• All treatments were applied
using a spray volume equivalent to
25 gallons per application.
continued on back.
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Simply Sustainable. Always Effective.
Table 1. Treatments and Rates
Treatment
Figure 1. OxiDate 2.0
and Xanthomonas Leaf Blight
Rate/Acre
N/A
1. Untreated Control
2. OxiDate 2.0 + Kinetic
(Non-Ionic Surfactant)
100
The Xanthomonas leaf blight infection of the susceptible
transplanted yellow variety ‘Granero’ responded well to
inoculation with the bacterial isolate collected previously
from eastern Colorado. OxiDate 2.0 provided excellent control
of the bacteria as noted by the significant reduction in percent
of foliar damage on one or both evaluation dates and reduced
effects of the pathogen when compared to the control that has
nearly 70% damage on either evaluation date. Total yield was
increased by up to 8.0% in OxiDate 2.0 treatment.
Weekly applications of OxiDate 2.0 in combination with a nonionic surfactant can provide excellent control of BLB in Onions.
When infection is already well established, OxiDate 2.0 can
be rotated with residual bactericides such as copper based
formulations to provide additional protection. Rotations with
OxiDate 2.0 can reduce the number of copper applications
and thereby decrease the total amount of residual copper that
gets released into the environment. OxiDate 2.0 can also be an
excellent tool in disease resistance management.
80
60
40
20
0
Untreated
OxiDate 2.0
1.0% v/v
August 2
August 8
Figure 2. OxiDate 2.0
and Onion Yield
25
Yield (lbs./25 sq. ft.)
Summary & Results:
% Bacterial Leaf Blight
1.0% v/v + 0.125% v/v
20
15
10
5
0
For full results, please contact BioSafe Systems.
Untreated
Total
LLC
1.888.273.3088 | www.biosafesystems.com
©2013 Copyright BioSafe Systems LLC. OxiDate® 2.0 is a registered trademark of BioSafe Systems, LLC.
Always read and follow label directions. AG13–71
OxiDate 2.0
1.0% v/v
Jumbo
Medium